1. Field of the Invention
The present invention relates to a liquid crystal display unit for use in a personal computer, a work station, or the like, and particularly relates to a technique which is effectively applicable to narrowing of a frame of a liquid crystal display unit or to thinning of the liquid crystal display unit.
2. Description of the Related Art
STN (Super Twisted Nematic) or TFT (Thin Film Transistor) type liquid crystal display modules are widely used as display units in notebook type personal computers and so on.
Such a liquid crystal display module is constituted by a liquid crystal display panel having a drive circuit portion disposed circumferentially, and a backlight unit for irradiating the liquid crystal display panel.
For example, such a backlight unit is constituted by a liquid guide body, a cold cathode fluorescent tube, a diffusion sheet, a lens sheet (also called a prism sheet), and a reflection sheet, which are received in a mold. The light guide body is provided to guide light emitted from a light source toward a position distanced from the light source so as to uniformly irradiate the whole of the liquid crystal display panel with the light. The cold cathode fluorescent tube is a linear light source disposed in the vicinity of a side surface of the light guide body so as to be parallel with the side surface of the light guide body along the side surface. The diffusion sheet is disposed on the light guide body. The lens sheet is disposed on the diffusion sheet. The reflection sheet is disposed to extend under the light guide body.
Incidentally, such a technique is, for example, disclosed in JP-B-60-19474 and JP-U-4-22780.
FIG. 13 is a schematic view for explaining an example of a mounting method for mounting the above-mentioned liquid crystal display module on a notebook type personal computer.
In FIG. 13, the reference numerals 100 and 101 represent outer and inner casings of a display portion of the notebook type personal computer, respectively. As shown in FIG. 13, a liquid crystal display module 102 is fixed to the outer casing 100 of the display portion of the notebook type personal computer by mounting screws 120 through a side beam 110.
To this end, inserters into which the mounting screws 120 are screwed are embedded in the mold of the liquid crystal display module 102.
Incidentally, although the side beams 110 and the mounting screws 120 are provided on opposite sides of the liquid crystal display module 102, the side beam 110 and the mounting screws 120 on one side are omitted to illustrated in FIG. 13.
FIG. 14 is a main portion sectional view showing the state where the liquid crystal display module shown in FIG. 13 has been mounted on the notebook type personal computer by a conventional mounting method.
Incidentally, FIG. 14 shows a sectional structure cut off in the moving direction of the mounting screws 120 shown in FIG. 13.
As shown in FIG. 14, the conventional liquid crystal display module has inserters 13 at four places (only one of which is shown in FIG. 14) in side surfaces of a mold 14.
Then, each of the mounting screws 120 is screwed into the corresponding inserter 13 through holes formed in the outer casing (for example, plastic casing) 100 of the display portion of the notebook type personal computer, the metal side beam 110, and a frame 4. Thus, the liquid crystal display module is mounted on the notebook type personal computer.
Incidentally, in FIG. 14, SUB1 represents a TFT substrate; SUB2, a color filter substrate; POL1 and POL2, polarizing plates; 4, a frame; 5, a liquid crystal display panel; 6 and 8, diffusion sheets; 7, a lens sheet; 9, a light guide body; and 10, a reflection sheet. These parts will be described later.
As shown in FIG. 14, when the liquid crystal display module is mounted on the notebook type personal computer by use of the inserters 13, external vibration or impact is applied directly to the side walls of the mold 14 through the mounting screws 120 because the inserters 13 are embedded in the side walls of the mold 14.
Thus, as shown in FIG. 15, the mold 14 is bent so that the light guide body 9 and the like are bent consequently. In the worst case, local stress is applied to the liquid crystal display panel 5.
Incidentally, in FIG. 15, the arrows show that the mold 14 is bent so that the light guide body 9 and the like are bent consequently.
Thus, there was a problem that the gap length of the liquid crystal display panel 5 (that is, the distance between the TFT substrate (SUB1) and the color filter substrate (SUB2)) varied so that the display screen of the liquid crystal display panel 5 rippled to spoil the display quality of the liquid crystal display panel 5 significantly.
The present invention was developed to solve the foregoing problem in the background art. It is an object of the present invention to provide a technique in a liquid crystal display unit in which external vibration or impact is prevented from being applied directly to a housing member through mounting screws for fixing the liquid crystal display unit to an outer casing, so that the display quality of the display screen displayed on a liquid crystal display device can be improved.
It is another object of the present invention to provide a technique in a liquid crystal display unit in which the degree of freedom in the attachment positions of mounting screws for fixing the liquid crystal display unit to an outer casing can be improved.
The aforementioned and other objects and novel features of the present invention will be made clear in the description of this specification and the accompanying drawings.
The summaries of typical aspects of the invention disclosed in this specification will be described briefly as follows.
That is, the present invention is applied to a liquid crystal display unit produced in the following manner. That is, a frame member (frame-like member) is fitted to a housing member (represented by a member known as a mold) for housing constituents (such as a liquid crystal display panel, a light source, optical sheets, etc.) of the liquid crystal display unit so as to form a so-called liquid crystal display module. This liquid crystal display module is fixed to an outer casing. Then, the liquid crystal display unit is completed.
For example, the housing member has a main surface and side surfaces formed around the main surface. Optical parts which are constituents of the liquid crystal display unit are housed on the main surface surrounded by the side surfaces.
In the case of a sidelight liquid crystal display module, a reflector, a light guide plate, optical sheets such as a light diffusion sheet, a prism sheet, and so on, and a liquid crystal display panel are laminated on one another on the main surface in this order.
In the case of a direct backlight liquid crystal display module, a light source unit constituted by a reflector and a plurality of fluorescent tubes fixed to the reflector, a light diffusion plate, optical sheets as described above, and a light crystal display panel are laminated on one another on the main surface in this order.
According to the present invention, in such a liquid crystal display unit, mounting members having threaded holes into which mounting screws for fixing the liquid crystal display unit to an outer casing are screwed are disposed between the side surfaces (side walls) of the housing member and the side walls of the frame member.
Then, each of the mounting members is designed so that the areas in which the threaded holes are provided operate elastically in the moving direction of the mounting screws.
In an embodiment of the present invention, each of the mounting members is constituted by a first side in which the threaded holes are provided and which extends along the side surface of the housing member, and a second side which is fixed to the housing member. The areas of the first side in which the threaded holes are provided operate elastically in the moving direction of the mounting screws.
Further, in a preferred embodiment of the present invention, notches are provided in each area of the first side in which the threaded hole is provided. The notches correspond to two sides of a quadrangle which includes the threaded hole and which surrounds each area of the first side in which the threaded hole is provided.
Further, in a preferred embodiment of the present invention, the first side has notches in each area of the first side in which the threaded hole is provided. The notches are disposed on opposite sides of each threaded hole in the extending direction of the housing-member.
Further, in a preferred embodiment of the present invention, the second side of each of the mounting members is fixed to the housing member by bonding or by mechanical means.
Further, a preferred embodiment of the present invention, the second side of each of the mounting members is fixed to the housing member by in-mold molding.
Further, in a preferred embodiment of the present invention, each of the side surfaces of the housing member has insertion holes to which the forward end portions of the mounting screws are inserted, and the diameter of each insertion hole is made larger than the diameter of the corresponding mounting screw.
Further, in a preferred embodiment of the present invention, each of the side walls of the housing member has groove portions to which the forward end portions of the mounting screws are inserted while a certain gap is maintained between each mounting screw and the wall of the groove portion.
Further, in a preferred embodiment of the present invention, the second sides of the mounting members and the housing member have means respectively for positioning the mounting members.
Further, in a more preferred embodiment of the present invention, the mounting member positioning means of the housing member are protrusion portions, and the mounting member positioning means of the second sides are holes into which the protrusion portions of the housing member are fitted.
Further, in a preferred embodiment of the present invention, the mounting members or the areas of the first sides in which the threaded holes are provided are formed out of an elastic material.
According to the aforementioned means, the mounting members fixed to the housing member are provided, and each of the mounting members has areas in each of which the threaded hole is provided and which are designed to operate elastically in the moving direction of the mounting screws. It is therefore possible to prevent external vibration and impact from being applied directly to the housing member through the mounting screws for fixing the liquid crystal display unit to an outer casing.
Thus, it is possible to improve the display quality of the display screen displayed on the liquid crystal display device.
In addition, according to the aforementioned means, the threaded holes provided in the mounting members can be provided in desirable positions in the thickness direction of the liquid crystal display unit. Thus, it is possible to improve the degree of freedom in the positions where the mounting screws are attached.